I get why they defected from the Emperor. If I had to swallow the garbage pumped out on an hourly basis by the guy I'd go to the dark side too. But Roboute had a better idea of the emperor then the Chaos Primarchs; he (Emperor) means good but truthfully is a piece of trash.

I believe so, now I don't really follow the HH books but talking to people who have

in the latest book, , Mortaion has a 180 and LOVE chaos despite previously having second thoughts about his side, basically Fulgrim all over again. And even if I don't follow the HH and only know info about Mortarion is basicly background and Mortarion's Heart Audio Drama I can just tell he only became cool after becoming a Deamon Prince, like some GrimDark Transgender.Horus got powered up thanks to entering the DBZ hyperbolic time chamberAnd the Emperor did indeed made a deal with the Chaos Gods in order to make the PrimarchsOh and McNeil brought in his special Iron Warroir snowflake

Before Emperor found Mortarion, Promarch wanted to slay a man, who treated him as a son since he came on Barbarus. He believed he's the only one who can do it, and when he reached the man' lair, toxic gasses turned out to be too poisonous even for him. Then' in the moment that was supposed to be Mortarion's great victory, the Emperor came and slayed creature easily. That' plus Destroyer Plauge and that he wasn't, as I see it, all that happy to create Imperium of easygoing billions rulled by Emperor, was enough for him to join Horus.

maybe, maybe )) i kinda was inspired by some miniature. And, besides... i guess you can only say "sickly" comparing to.. Russ maybe, since all primarchs are still posess way better physique then any average space marine.

Oh, yeah, certainly. I don't necessarily mean sickly, like, stick thin, but I think somewhere in Visions of Heresy they describe him as kinda lanky and morbid on the skin, even before corruption, at least compared to say Horus/Russ/Dorn.